After accessing a @ManyToOne(fetch = FetchType.LAZY) property inside a session, shouldn't it be possible to access the same property again after the session has been closed?

Hibernate (3.3.1.GA) appears to think not:

org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:86)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:140)
at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190)
at test.Foo_$$_javassist_8.toString(Foo_$$_javassist_8.java)
...

Is this a bug, feature, or perhaps I'm doing something wrong?

I guess it depends on which side of the relation the original get request was for.

Here's as example:

foo.getLazyBar().toString()

This call succeeds when I call it the first time (within a session). The lazyBar is loaded I get the toString(). Then I close the session and run the exact same statement again -- but now it fails with a LazyInitializationException. This is surprising as I'd expect FetchType.LAZY on an @ManyToOne to behave like it does on lazy collections (i.e. first access initializes the collection, thereafter it can be used outside of the original session).

So the question is: Is this supposed to work?

Well, your understanding is correct. If loaded, the relationship stays there.

There must be something peculiar about our code. I'm wondering if you somehow put the object out of scope in your second iteration.

Maybe you can show us more code?

Thanks for confirming that this is supposed to work.

How can the object go out of scope while I'm still referencing it (unless javassist is using weak/soft references)?

I'll try to come up with a simple test case...

Turns out the initialized object was sneakily being replaced with an uninitialized one -- my bad. Case closed :-)

Heh...Thanks for the follow up. Sometimes the most difficult problems to solve have the simplest solutions.